Electronic device provided with an integrated conductor element and fabrication method

ABSTRACT

An electronic device includes a support plate having a mounting face and an electrical connection network. An integrated circuit chip is mounted on the mounting face and linked to the electrical connection network. An en encapsulation block embeds the integrated circuit chip. An additional element made of an electrically conductive material is at least partly embedded within the encapsulation block. The additional conductive element has a main portion extending parallel to the support plate and has a secondary portion that is linked electrically to the integrated circuit chip. An opening is formed in the encapsulation block, and the secondary portion extends into that opening to make the electrical link. The additional conductive element may be an antenna.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application from U.S. patentapplication Ser. No. 15/050,253 filed Feb. 22, 2016, which claimspriority from French Application for Patent No. 1557999 filed Aug. 28,2015, the disclosure of which is incorporated by reference.

TECHNICAL FIELD

The present invention relates to the field of electronic devices.

BACKGROUND

Known electronic devices, generally of parallelepipedal form, comprise asupport plate, including an electrical connection network, an integratedcircuit chip mounted on one of the faces of the support plate and anencapsulation block in which the chip is embedded. The chip is linked tothe network of the support plate by electrical connection elements suchas balls, interposed between the support plate and the chip, or byelectrical connection wires embedded in the encapsulation block.

Such electronic devices are mounted on printed circuit plates, generallyvia electrical connection elements such as balls, linking the electricalconnection network of the support plates and the electrical connectionnetwork of the printed circuit plates.

When the chips generate radiofrequency signals that have to betransmitted or process received radiofrequency signals, the transmissionor reception antennas are produced on the printed circuit plates. Theelectrical signals follow very long resistive paths which are formed bylines of the electrical connection network of the printed circuitplates, the electrical connection elements between the printed circuitplates and the support plates, lines of the electrical connectionnetwork of the support plates and the electrical connection elementsbetween the support plates. Such paths further depend on the quality ofthe interconnections obtained from the fabrication.

The above provisions constitute a handicap notably when the necessarydimension of the antennas, for the transmission of radiofrequencysignals at frequencies of the order of a gigahertz or above, even verymuch greater than a gigahertz, become reduced.

SUMMARY

According to one embodiment, an electronic device is proposed thatcomprises a support plate having a mounting face and including anelectrical connection network, at least one integrated circuit chip,mounted on said mounting face of the support plate and linked to saidelectrical connection network, an encapsulation block in which the chipis embedded, this encapsulation block extending over the chip and aroundthe latter on said mounting face of the support plate, and at least oneadditional element made of an electrically conductive material, at leastpartly embedded in said encapsulation block, this additional conductiveelement having at least one main portion extending parallel to saidsupport plate and having at least one secondary portion linkedelectrically to said chip.

Said secondary portion of the additional conductive element can belinked to at least one electrical contact formed on said mounting faceof said support plate at a distance from the periphery of the chip.

Said secondary portion of the additional conductive element can belinked to at least one electrical contact formed on a front face of saidchip.

Said secondary portion of said additional conductive element can befolded back towards the support plate relative to its main portion.

A soldering material can be interposed between said secondary portion ofsaid additional conductive element and said electrical contact of thesupport plate.

Said encapsulation block can have a cavity at least partially revealingsaid main portion of said additional conductive element.

Said main portion of said additional conductive element can extend overand at a distance from the chip.

Said additional conductive element can constitute a radiofrequencyantenna.

Said encapsulation block can comprise two superposed parts between whichsaid additional conductive element extends.

A method for fabricating an electronic device is also proposed, in whichthere is available a primary electronic device comprising a supportplate, an integrated circuit chip mounted on a mounting face of thesupport plate and a primary encapsulation block extending over the chipand around the chip on said mounting face of the support plate, theencapsulation block having a front face parallel to the support plate;and an additional element made of an electrically conductive material,formed so as to have at least one main portion and at least onesecondary portion.

The method comprises: producing a hole through said primaryencapsulation block of the primary electronic device, from its frontface, to at least partially reveal an electrical contact of saidmounting face of said support plate or of the chip; installing saidadditional conductive element in a position such that its main portionextends over said front face of the primary encapsulation block and itssecondary portion is linked to said electrical contact in said hole; andproducing an additional encapsulation block on said primaryencapsulation block of said primary electronic device, the primaryencapsulation block and the additional block constituting a finalencapsulation block in which said additional conductive element is atleast partially embedded.

The method can comprise: having available an additional conductiveelement having a secondary portion folded back relative to its mainportion and installing the additional conductive element in a positionsuch that this secondary portion is engaged in said hole of theencapsulation block of the primary electronic device.

The method can comprise: linking the secondary portion of saidadditional conductive element to said electrical contact by solderingmaterial.

The method can comprise: producing a groove in the front face of theprimary encapsulation block of the primary electronic device andinstalling at least said main part of said additional conductive elementin this groove.

The method can comprise: at least partly bonding said additionalconductive element on the front face of the primary encapsulation blockof the primary electronic device.

The method can comprise: producing a void in the additionalencapsulation block, so as to partially reveal said main part of saidadditional conductive element.

The method can comprise: before installing said additional conductiveelement, producing a void in said primary encapsulation block of theprimary electronic device and installing said additional conductiveelement in a position such that said main portion of this additionalconductive element totally covers and closes this void.

In an embodiment, a method for fabricating an electronic devicecomprises: producing a hole extending through a primary encapsulationblock of a primary electronic device comprising a support plate, anintegrated circuit chip mounted on a mounting face of the support plateand said primary encapsulation block extending over the integratedcircuit chip and around the integrated circuit chip on said mountingface of the support plate, the encapsulation block having a front faceparallel to the support plate, said hole at least partially revealing anelectrical contact; forming a conductive element to include a mainportion and a secondary portion with a bend in the conductive elementpresent between the main and secondary portions; installing the formedconductive element in a position such that the main portion is carriedby a front face of the primary encapsulation block and the secondaryportion extends into said hole; and electrically connecting thesecondary portion to said electrical contact.

BRIEF DESCRIPTION OF THE DRAWINGS

Electronic devices and their fabrication methods will now be describedas exemplary embodiments, illustrated by the drawing in which:

FIG. 1 represents a cross section of an electronic device;

FIG. 2 represents a plan view of the electronic device of FIG. 1;

FIG. 3 represents a step of fabrication, in cross section, of theelectronic device of FIG. 1;

FIG. 4 represents another step of fabrication, in cross section, of theelectronic device of FIG. 1;

FIG. 5 represents another step of fabrication, in cross section, of theelectronic device of FIG. 1;

FIG. 6 represents another step of fabrication, in cross section, of theelectronic device of FIG. 1;

FIG. 7 represents a cross section of another electronic device;

FIG. 8 represents a cross section of another electronic device;

FIG. 9 represents a cross section of another electronic device; and

FIG. 10 represents a plan view of the electronic device of FIG. 9.

DETAILED DESCRIPTION

As illustrated in FIGS. 1 and 2, according to an exemplary embodiment, afinal electronic device 1 comprises a support plate 2, including anintegrated electrical connection network 3, an integrated circuit chip 4mounted on a front mounting face 5 of the support plate 2 and a finalencapsulation block 6 in which the chip 4 is embedded and which extendsover the chip 4 and around the latter, on the mounting face 5 of thesupport plate 2, such that the electronic device 1 takes the form of aparallelepiped.

According to a variant embodiment represented, the integrated circuitchip 4 is mounted on the mounting face 5 of the support plate 2 viaelectrical connection elements 7, such as balls, which selectively linkthe chip 4 and the electrical connection network 3. According to anothervariant embodiment, the chip 4 could be bonded onto the mounting face 5of the support plate 2 and be linked to the electrical connectionnetwork 3 by electrical connection wires embedded in the encapsulationblock 6.

The electronic device 1 further comprises an additional integratedelement 7′ made of an electrically conductive material, preferablyrigid, embedded in the encapsulation block 6.

The additional conductive element 7′ comprises a main portion 8 whichextends parallel to the mounting face 5 of the support plate 2 and asecondary portion 9 which links the main portion 8 to an electricalcontact 10 of the electrical connection network 3 via a solderingmaterial 11, this electrical contact 10 being formed on the mountingface 5 of the support plate 2 and being situated at a distance from andoutside the periphery of the chip 4 and at a distance from and insidethe periphery of the encapsulation block 6.

According to a variant embodiment represented, the main portion 8 of theadditional conductive element 7′ extends over and at a distance from thechip 4 and the secondary portion 9 is folded back towards the supportplate 2 relative to the main portion 8.

The additional conductive element 7′, prefabricated, can for example beformed by stamping an elongate metal sheet of which the main portion 8is flat above and at a distance from the support plate 2 and the chip 4,a secondary portion 9 being able to be reduced to a folded-back tab. Theadditional conductive element 7′ can be obtained by cutting a metalplate and forming at the same time or after the cutting.

The electronic device 1 can be provided with external electricalconnection elements 12, such as balls, arranged on electrical contacts13 of the electrical connection network 3 formed on a face 14 of thesupport plate 2, opposite the mounting face 5, these electrical contacts13 being linked selectively to the electrical connection network 3 ofthe support plate 2.

The electronic device 1 can be produced as follows.

As illustrated in FIG. 3, there is a primary electronic device 15available, prefabricated, which comprises the support plate 2, the chip4 mounted as described previously and a primary encapsulation block 16in which the chip 4 is embedded and which extends, around the chip 4,over the mounting face 5 of the support plate 2. The primaryencapsulation block 16 has a front face 17 which is parallel to thesupport plate 2 and which extends over and at a distance from the chip4.

As illustrated in FIG. 4, a hole 18 is produced locally through theprimary encapsulation block 16, from its front face 17, at a pointsituated between the periphery of the chip 4 and the periphery of theprimary encapsulation block 16, so as to reveal the electrical contact10. Then, a drop of a soldering material 11 is deposited at the bottomof the hole 18 on the electrical contact 10.

Next, as illustrated in FIG. 5, the additional conductive element 7′,prefabricated by forming and cutting, is installed on the primaryencapsulation block 16, in a position such that its primary portion 8extends over the front face 17 and its secondary portion 9 is engaged inthe hole 18, the end of the secondary portion coming into contact on thesoldering material 11.

Then, optionally, at least the part of the main portion 8 furthest awayfrom the secondary portion 9, for example, is bonded onto the front face17 using a spot of glue 19. According to a variant embodiment,illustrated optionally in FIG. 2, a positioning groove 16 a emerging inthe hole 18 could be produced in the front face 17 of the primaryencapsulation block 16, the main portion 8 of the additional conductiveelement 7 being able to be inserted into this groove 16 a and thuspositioned and held in place.

Next, the electrical device 15 is passed into an oven to produce thesoldering of the secondary portion 9 of the additional conductiveelement 7′ on the electrical contact 10 via the soldering material 11,the additional conductive element 7′ being held by virtue of the spot ofglue 19.

Next, as illustrated in FIG. 6, an additional encapsulation block 20 isproduced on the primary encapsulation block 16 so as to cover theadditional conductive element 7′, such that the primary encapsulationblock 16 and the additional encapsulation block 20 constitute the finalencapsulation block 6 and that the final electronic device 1 is obtainedas described previously with reference to FIGS. 1 and 2.

As illustrated in FIG. 7, according to another exemplary embodiment, thefinal electronic device 1 can be considered as a new primary electronicdevice 21, on which steps equivalent to the steps described above withreference to FIGS. 4 to 6 are carried out, for example as follows.

A hole 22 is produced in or through the encapsulation block 6 from itsfront face 6 a, at a point different from that of the previous hole 18,so as to reveal another electrical contact 23 of the electricalconnection network 3, this other electrical contact 23 being formed onthe mounting face 5 of the support plate 2.

Then, a drop of a soldering material 24 is deposited on this electricalcontact 23 at the bottom of the hole 22.

Next, another additional conductive element 25, equivalent to theadditional conductive element 7, is installed, with a main portionplaced on the front face 6 a of the encapsulation block 6 and asecondary part engaged in the hole 22 to be placed on the drop 24. Then,the soldering is done.

Finally, another additional encapsulation block 26 is produced on theencapsulation block 6, covering the other additional conductive element25, so as to form another final encapsulation block 27 consisting of theencapsulation block 6 and of the additional encapsulation block 26.

A final electronic device 28 is then obtained that is equipped with thetwo additional conductive elements 7′ and 25, embedded in this finalencapsulation block 27.

As illustrated in FIG. 8, according to another exemplary embodiment, afinal electronic device 28 is differentiated from the electronic device1 described previously by the fact that it comprises an additionalconductive element 29 of which the secondary portion 30 is, this time,directly linked to a specific electrical contact 31 provided on thefront face 32 of the chip 4. The specific electrical contact 31 canresult from the formation of an electrical link passing through thesubstrate from the integrated circuit chip 4, known by the name TSV(Through Silicon Via).

In this exemplary embodiment, the fabrication step, equivalent to thatdescribed with reference to FIG. 4, consists in producing a hole 33through the primary encapsulation block 16, at a point situated over thechip 4, so as to reveal the electrical contact 31. The subsequent stepsof installation of an additional conductive element 7 and of productionof an additional encapsulation block 20 are equivalent to thosedescribed with reference to FIGS. 5 and 6.

As illustrated in FIGS. 9 and 10, according to another exemplaryembodiment, a final electronic device 34 is differentiated from theelectronic device 1 described previously by the fact that it comprises aformation of a cavity 35 in a final encapsulation block 6, open outwardsand partially revealing the main portion 8 of the additional conductiveelement 7′.

The cavity 35 comprises an opening 36 formed through the additionalencapsulation block 20, to the main portion 8 of the additionalconductive element 7′. This opening 36 is produced after the step ofproduction of the additional encapsulation block 20.

The cavity 35 further comprises a void 37 formed under the main portion8 of the additional conductive element 7′, for example between the frontface 38 of the chip 4 opposite the support plate 2 and this main portion8.

The void 37 is produced in the step described with reference to FIG. 4,before the placement of the additional conductive element 7′. The mainportion 8 of the additional conductive element 7′ completely covers thevoid 37 so that, during the step of production of the additionalencapsulation block 20, the material forming this block 26 does notpenetrate into this void 37.

Moreover, the front face 38 of the chip 4 can be covered by a metalliclayer 39. The main portion 8 of the additional conductive element 7′ canserve to form a radiofrequency antenna and the metallic layer 39 can inthis case serve as ground plane for said antenna.

According to a variant embodiment, the main portion 8 of the additionalconductive element 7′ could be perforated.

A cavity equivalent to the cavity 35 could be produced in the electronicdevices described with reference to FIGS. 7 and 8.

In the case where the main portion 8 of the additional conductiveelement 7′ forms a radiofrequency antenna, the cavity 35 and the void 37formed under the main portion 8 of the additional conductive element 7′offer the advantage of making it possible to access the main portion 8to deform it and/or perforate it, in order to adjust the electromagneticcharacteristics of the antenna. This adjustment operation can beperformed after the fabrication of the final device 34 is finished andthe latter has been mounted and tested in the desired application.

The electronic devices which have just been described can be obtained bya collective fabrication on a common support wafer, as is known in themicroelectronics field. The encapsulation blocks and the additionalencapsulation blocks can be obtained by spreading a liquid material, forexample an epoxy resin, then by hardening this material.

Of course, the additional conductive elements of the electronic devicescan take any desired topographic forms.

The additional conductive elements of the electronic devices which havejust been described, included in the final encapsulation block, canadvantageously constitute electromagnetic antennas for thetransmission/reception of radiofrequency signals at very highfrequencies (up to a gigahertz or above a gigahertz, even severalhundred gigahertz), linked to the chip 4 by short electrical connectionpaths, via the electrical connection network of the support plate 2(FIG. 1) or directly (FIG. 8).

1. A method for fabricating an electronic device, comprising: producinga hole extending through a primary encapsulation block of a primaryelectronic device comprising a support plate, an integrated circuit chipmounted on a mounting face of the support plate and said primaryencapsulation block extending over the integrated circuit chip andaround the integrated circuit chip on said mounting face of the supportplate, the encapsulation block having a front face parallel to thesupport plate, said hole at least partially revealing an electricalcontact; forming a conductive element to include a main portion and asecondary portion with a bend in the conductive element present betweenthe main and secondary portions; installing the formed conductiveelement in a position such that the main portion is carried by a frontface of the primary encapsulation block and the secondary portionextends into said hole; and electrically connecting the secondaryportion to said electrical contact.
 2. The method of claim 1, whereinsaid electrical contact is an electrical contact on said mounting faceof said support plate.
 3. The method of claim 1, wherein said electricalcontact is an electrical contact on a face of the integrated circuitchip.
 4. The method of claim 3, further comprising producing a throughsilicon via in said integrated circuit chip, wherein said electricalcontact on the face of the integrated circuit chip is electricallyconnected to said through silicon via.
 5. The method of claim 1, furthercomprising producing an additional encapsulation block on said primaryencapsulation block with the additional encapsulation block at leastpartially embedding the conductive element.
 6. The method of claim 5,further comprising producing a void in the additional encapsulationblock that at least partially reveals said main portion of saidconductive element.
 7. The method of claim 6, further comprisingproducing another void in the primary encapsulation block underneath apart of said main portion of said conductive element.
 8. The method ofclaim 5, wherein producing the additional encapsulation block comprisesfilling said hole with material of said additional encapsulate block. 9.The method of claim 5, further comprising: producing a further holeextending through both the primary encapsulation block and theadditional encapsulation block, said further hole at least partiallyrevealing a further electrical contact; forming a further conductiveelement to include a main portion and a secondary portion with a bend inthe further conductive element present between the main and secondaryportions; installing the formed further conductive element in a positionsuch that the main portion is carried by a front face of the additionalencapsulation block and the secondary portion extends into said furtherhole; and electrically connecting the secondary portion to said furtherelectrical contact.
 10. The method of claim 1, wherein forming comprisesfolding said secondary portion back relative to said main portion atsaid bend.
 11. The method of claim 1, wherein electrically connectingcomprises soldering the secondary portion to said electrical contact.12. The method of claim 1, further comprising: producing a groove in thefront face of the primary encapsulation block; and installing at leastsaid main portion of said conductive element in said groove.
 13. Themethod of claim 1, further comprising: at least partly bonding saidconductive element on the front face of the primary encapsulation block.14. The method of claim 1, further comprising: before installing saidconductive element, producing a void in said primary encapsulationblock; and wherein installing said conductive element comprisespositioning said main portion of the conductive element over said void.15. The method of claim 14, wherein said installed conductive elementtotally covers and closes said void.
 16. The method of claim 15, furthercomprising: producing an additional encapsulation block on said primaryencapsulation block with the additional encapsulation block at leastpartially embedding the conductive element.
 17. The method of claim 16,further comprising producing a void in the additional encapsulationblock that at least partially reveals said main portion of saidconductive element.